Various holding devices, like tool holders and work holders for machining workpieces, are known including mechanically actuated and hydraulically actuated types. Such “holders” typically have a sleeve to hold a workpiece or tool by collapsing around the workpiece or tool or by expanding within the workpiece or tool. Mechanically actuated holders usually have a collet that is generally cylindrical and includes a number of leaves that are defined by relief slots that allow the collet to radially expand and contract. The collet also has a tapered portion that cooperates with a corresponding tapered portion of an actuating mechanism that is linearly displaceable to impose a linear force on the tapered portion of the collet. Such linear displacement is converted to radial displacement of the collet via the corresponding tapered portions. Hydraulically actuated holders include those which have one or more chambers containing a fluid which, when pressurized, radially displaces a bladder. In turn, the displaced bladder displaces a circumferentially continuous or slotted sleeve (collet) into engagement with a workpiece or tool.